Turkish Prime Minister Recep Tayyip Erdogan Faces Test in Istanbul

Corruption Scandal Puts a Mayoral Race in Limelight

ISTANBUL—The political future of Turkish Prime Minister Recep Tayyip Erdogan, his long hold on power weakened by a growing corruption scandal, now partly depends on a mayoral vote to be held on Sunday in this city where he rose to prominence 20 years ago.

In municipal elections across Turkey on Sunday, no race is likely to test the popularity of Mr. Erdogan and his Islamist-rooted Justice and Development Party, or AKP, ahead of...